Dielectric properties of BT-LMT mixed ceramics

Abstract Two types of ceramics of (1 −  x )BaTiO 3 – x La(Mg 1/2 Ti 1/2 O 3 ) with x  = 0.025 (0.975BT–0.025LMT) were dielectrically investigated over the extended frequency range. Dielectric studies have been performed in the frequency range from 20 Hz to 10 GHz within the temperature interval of −170–230 °C. It is shown, that in these ceramics BT-type three phase transitions become diffuse and typical relaxor type dispersion is observed. Maxima of both imaginary and real parts of the dielectric permittivity are shifted to lower temperatures in comparison with pure BT and in the temperature ranges close to the phase transitions show a strong frequency-dependent behaviour. The distribution function of the relaxation times g ( τ ) was calculated from dielectric measurements for both measured ceramics—homogenous and non-homogenous. Dynamics of the phase transitions are discussed.